Converting thread prefixes from IPB 3.2

I'm in the process of preparing to convert my site from IPB 3.2 to XenForo.

One issue I have come across during my test conversions is that the importer does not convert IPB's thread prefixes to the XenForo equivalent. My site does not depend extensively on prefixes so this isn't a showstopper but it would be nice to carry them over if possible.

Is there any way to do this? I'm open to manually extracting IPB SQL data, manipulating in Excel and inserting into the XF database if that's what it will take (I'm importing into an empty XF installation so thread IDs will remain the same).